Antenna mounting for a guided missile



Jan. 28, 1958 H. J. REIS ETAL 2 ANTENNA MOUNTING FOR A GUIDED MI SSILE Filed Sept. 9, 1954 4 Sheets-Sheet l GROUND STATION-A sedu/vq I INVENTORS firbg'lefijlew d Mllmm Klble y BY v ' ATTORNEY 1953 H. .1. RES ETAL ANTENNA MOUNTING FOR A GUIDED MISSILE Filed Sept. 9Q 1954 4 Sheets-Sheet 2 IN VENTORS .jyerberi Jfieis w ATTORNEY William Klalezy Jan. 28, 1958 RE|$ r 2,821;706

Y MOU D MI I INVENTORS fih'berldlfleis d William Klbl y ATTORNEY United States Patent' 2,821,706 ANTENNA MOUNTING son A GUIDED MISSILE Herbert 'J. Reis and William V. Foley, Middle River,

Md., assignors to The Glenn L. Martin Company, Middle River, Md., a corporation of Maryland Application September 9, 1954, Serial No. 454,899 13 Claims. (Cl. 343-705) This invention relates to an antenna assembly and more particularly to an antenna assembly for mounting on a guided missile.

Guided missiles are becoming an ever more important phase of ordnance materiel. One type of missile is launched from the ground and directed by ultra high frequency'energy to the target. Control stations are strategically located so as to accurately guide the missiles trajectory. These stations are quite some distance from the missile, particularly when the missile is approaching the target area. If the transverse elevation radiation patterns of the transmitting antennas of the missile are not properly allocated with respect to the control stations, saidstations cannot accurately control the missile flight path. Since the missile, despite gyro systems, tends to roll around its flight axis, the radiation pattern is not constant in direction. Therefore, when the control stations are at such great distances from the missile as to be in effect at the horizon, the roll of the missile, and resultant change of direction of radiation pattern, is likely to cause the control station to be beyond the limits of the pattern of transmitted energy from the missile. So the control station loses the missile and-the trajectory is in error.

It is an object of this invention to provide a novel antenna assembly for a guided missile which greatly reduces' the chance of a control station losing the missile during flight, due to roll of said missile.

More specifically, it is an object of this invention to provide an antenna assembly for a guided missile that directs more of the energy, in the antenna transverse elevation radiation pattern, above the horizon.

It is another object of the invention to achieve the immediately foregoing object, namely, the direction of more of the energy of the transverse radiation pattern above the horizon, without seriously affecting the aerodynamic properties of the missile.

These and other objects will be apparent from the description of the accompanying drawings:

Figure 1 is a perspective view of a guided missile showing on the bottom of the fuselage thereof the antenna assembly constructed in accordance with this invention;

Figure 2 is a diagrammatic illustration of the antenna assembly transverse elevation radiation pattern according to assemblies used in the prior art;

Figure 3 is a view similar to Figure 2 but illustrating the radiation pattern using the antenna assembly of the present invention;

Figure 4 is a fragmentary side elevation showing the antenna assembly of the present invention as mounted on the bottom of the fuselage of the guided missile; Figure .5 is a view taken along the line 5-'-5 of Figure4i F u e 6 is} ie tales alo g the line H of Fisme the controlled flight of the missile.

Figure 7 is a plot of the transverse elevation radiation pattern of a typical prior art antenna assembly; and

Figure 8 is a plot of a transverse elevation radiation pattern of an antenna assembly constructed in accordance with the present invention.

Turning now to Figure 1, the numeral 10 indicates the guided missile. The missile has the usual wings 11 and tail assembly 12. It also has an air scoop 13. On the bottom of the fuselage 14 is the antenna assembly constructed in accordance with this invention and is indicated by numeral 15.

As has been stated before it is the main object of this invention to provide an antenna assembly for mounting to a guided missile which assembly provides a radiation energy pattern better adapted to provide accurate control of the trajectory of the missile. One of the hazards during flight is that the missile will roll around its axis of flight.

Turning to Figures 2 and 3 there is illustrated in diagrammatic fashion the elfect that this roll will have on In Figure 2 there is shown in diagrammatic form an energy pattern using an antenna assembly of the prior art. The missile 10 is pictured as travelling in a direction directly at the viewer. The assembly includes the stub antennas which are flush with the skin of the bottom of the fuselage. One of the control stations is identified as Station A and line 16 is drawn between the stub antenna and Station A. It must be remembered that Station A is a considerable distance from the missile 10, particularly with relation to the altitude of the missile above the ground. For all intents and purposes Station A is on the horizon and consequently line 16 is substantially parallel to the ground line. Line 17 is drawn from the stub antenna, flush with the fuselage skin, tangent to the energy lobe 18. It can be seen from this figure that if the missile rolls in a clockwise direction, an angle theta, Station A will not receive any energy from the missile and the missile will therefore be out of control from Station A. Of course, it must be remembered that there are a plurality of these control stations, such as, for example, one on port side of the missile. The situation, of course, would be the same for a missile roll in one direction as in the other, since the plotting and guiding of the missile is dependent upon simultaneous reception of signals at all of the stations. The present invention presents an antenna assembly which increases the angle theta, and consequent- *ly the permissible roll, and for this attention is now directed to Figure 3.

In Figure 3 like numerals refer to like parts in Figure 2. It can be seen that the angle between lines 16 and 17 has been increased to theta plus phi. Conse quently the missile will be able to roll in a clockwise direction a larger number of degrees because of the present antenna assembly than was possible with the prior art antenna assembly as indicated in Figure 2. This is because the antenna assembly of the present invention directs more of its energy above the horizon, the horizon being indicated here as substantially equal to the line trated in Figures 2 and 3 will be discussed with relation to Figures 7 and 8. It is the purpose of Figures 2 and 3 to illustrate in a diagrammatic fashion the improvement made by the present system over the prior art system.

Turning now to Figure 4 there is shown a fragmentary side elevation of the antenna assembly and the means of 16. Actual plots made of the systems illusthe bottommost point thereon. As was illustrated in Figured this is intheusual case immediately back of the air scoop 13. The antennas 19 are fed from the transmitter-receiver assembly 21 by coaxial cables 22. The cables 22 are coupled to the antennas 19 bycoupling assemblies 23. The fairing'zt't' is illustrative of a preferred form of the invention in' which'two antennas are placed in moderate proximity and accommodatedby a single fairing, element. The contour of the" fairing 20 is generally a shallow dish-shaped or trough-shaped body and is shown as made up of two substantially semiconical end portions 201; and a connectingv wedge-shaped portion 2012, all joining to form a protuberance on the missile surface, said ports smoothly merging and blend ing with each other and with the surface of the missile fuselage 14. The side and end" surfaces of the fairing are shown as making an angle of about 30'withthe horizontal' plane when the missile is erect. That is to say, the sides or ends of the fairing preferably, although not necessarily, include between them an angle of about 120. The fairing includes a flange 24' riveted to the skin of the fuselage 14 to provide a smooth junction of fairing and fuselage and consequently a continuous and smooth ground plane for the antennas. The fasteners 25 mount the flange 24 and consequently the fairing 20 to the fuselage 14. A typicalassembly drops the antennas about 2 /2 inches below the skin of the fuselage. This is more clearly illustrated in Figure 5.

In Figure 5 the cross-sectional shape of the fairing is shown. This cross section is substantially constant for practically the entire length of the fairing. However, in the semi-conical portions at both ends, the depth and width of the cross-section decreases. to smoothly blend with the skin of the fuselage.

Turning to Figure 6 there is shown the means of mounting the antenna 19 to the fairing 20. In the form of the invention shown the antenna 19 is shown as a stub antenna, but it will be understood that any other antenna, such as an annular slot antenna, giving the characteristic radiation pattern known in the art as a stub pattern may be used, and such antennas are hereinafter referred to as stub pattern antennas. As can be seen in this figure, the coaxial cable 22 passes through an opening 26 in the fuselage 14. To strengthen this opening there is an annular plate 27 bolted by bolts 253 to the fuselage 14. The stub antenna 19 has an integral flange 29 which engages the bottom of the plate 30. The plate 30 has an aperture therein which receives the upward extension of the antenna 19. This plate 30' is mounted to the inWardly-turned'portion 51 of the fairing 20 by bolts 32. The bolts 32 engage in cleats 33, said cleats being held in position on the portion 31 by rivets 34. The stub antenna 19 has a second plate 55 which bears against the top of the plate 30 to thereby securely hold the stub antenna is position in the fairing.

Now turning to Figures 7'and 8 there are shown two plots of the radiation pattern ofdifferent stub antenna assemblies. In Figure 7 there is shown a plot of a typical antenna assembly of the prior art. Taking the 0-0 line as the horizon it can be seen that the half-power point, for instance on the right hand lobe, is located at 11. On the left hand lobe the angle is substantially less. However, turning to Figure 8, which is a typical plot of the antenna assembly constructed in accordance with this invention, the right hand plot shows a. half power point at close to 25. It can be seen, then, that in actual practice in accordance with a typical comparison between an assembly exemplary of the prior art and the assembly of the present invention the angle phi is approximately 14". This means thatv the missile with. the antenna assembly of the example hereindescribed-can stand'a roll of approximately 14 more than. the rol of a missile having an antenna assembly of the prior art.

What has been illustrated is one embodiment of this i11- vention. Other embodiments obvious from the teachings herein to those skilled in the-art are'contemplated to be" within the spirit and scope of the following claims.

What is claimed is:

1. An antenna assembly for a guided missile that comprises stub pattern antennas for transmitting radiant energy to a. remote location, and for receiving radiant energy therefrom. for guidingthe missile in flight, a fairing, said'fairing being substantially dish-shaped, means to mount said-fairing to the fuselage of said missile at approximately the lowest point on the fuselage, the fuselage having openings therein registering with the interior of said fairing which openings. provide passage therethrough for the electrical feed'connection s for said antennas, the bottom of saidfairing being provided with openings therein and means to mount said antennas in said openings, said fairing forming a ground plane for said antennas whereby the radiation from saidantennas extends above a horizontal plane passing throughsaid antennas.

2. An antenna assembly asdefined by claim I in which the base of said fairing has a flange therearound, said flange being mounted to said fuselage to provide a smooth substantially-uninterrupted ground plane for said antennas.

3'. An antenna assembly as defined by claim 1 in which the sides of said fairing include between them an. angle of about 4. An antenna assembly for a guided missile that comprises stub pattern antennas for transmitting radiant energy to a remote location, and for receivingv radiant energy therefromfo'r guiding said missile in. fiight, a fairing having a central portion and end portions contiguous therewith, said central portion being substantially V- shaped in. cross-section, said end portions being, substantially semi-conicaI and merging with the ends of. said central section to form a trough, the bases of. all. portions forming the fairing base, means to mount saidfairing base to the fuselage of said missile at approximately" the lowest point on said fuselage, said fusclagehaving openings therein registering with the interior of. said fairing which openings provide passage therethrough for the electrical feed connections for said antennas, the bottom of said fairing being provided with openings therein and means to mount said antennas in said openings.

5. An antenna assembly for a missile guided in flight by signals from ground stations comprising a fairing, mounted at its perimeter to the fuselage of. said missile and extending. over a portion thereof, the base portion of said fairing in spaced. relation to said fuselage, stub pattern antennas'extending through said fairing for transmitting' and receiving: information signals to and from said ground stations, means to mount said. antennas to said fairing whereby said fairing formsa ground plane for said antennas thereby forming. a radiation pattern extending substantially above a horizontal plane extending through said antennas, permitting. substantial roll of said missile without interrupting the signal pattern to and from said ground control stations.

6. An antenna assembly as defined by claim 5 in which said fairing is mounted to the bellyPortion of the missile fuselage.

7. An antenna assembly for a missile guidedin flight by signals from ground stations comprising a fairingv mounted at its perimeter to thefuselage of said missile extending. over a portion thereof and having the form of a protuberance smoothly blending with the surface of the missile, stub pattern antennas for transmitting and receiving information signals to and from said. ground stations, means to mount said antennas to said fairing, said antennas extending radially from. said fuselage through said fairing at a distance from said fuselage to permit signal pattern to and from said ground control stations.

8. An antenna assembly for a missile guided in flight by signals from ground stations comprising a fairing mounted at its perimeter to the fuselage of said missile and extending over a portion thereof with the base portion of said fairing in spaced relation to said fuselage, a stub pattern antenna for transmitting and receiving information signals to and from said ground stations, means to mount said antenna to said fairing, said antenna extending through said fairing at a distance from said fuselage to permit substantial roll of said missile without interrupting the signal pattern to and from said ground control stations.

9. An antenna assembly for an aircraft to enable the aircraft to communicate with ground stations comprising a fairing at substantially the lowest point on the fuselage, and at least one antenna for communication with the ground stations, said antenna being mounted so as to protrude through the lowermost portion of the fairing at a location substantially in alignment with a vertical plane passing through the longitudinal centerline of the aircraft fuselage, said fairing having sides tapering upwardly and outwardly from said antenna so as to form a ground plane created with respect to said antenna so that a substantial portion of the radiation pattern emanating from said antenna extends above a generally hori- Zontal plane passing through said antenna perpendicular to said vertical plane whereby said aircraft can undergo substantial roll without interrupting the signal communication with ground control stations.

10. An antenna assembly for an aircraft as described in claim 9 wherein the tapered sides of said fairing are placed so as to define an angle of approximately 120 therebetween.

11. An antenna assembly as described in claim 9 wherein said fairing is of an electrically conductive material.

12. An antenna assembly for an aircraft to enable the aircraft to communicate with ground stations comprising a fairing at substantially the lowest point on the fuselage, and antennas for transmitting and receiving information signals to and from the ground stations, said antennas being placed in spaced relation so that their respective signals will not interfere, and being mounted so as to protrude through the lowermost portion of the fairing, said fairing having sides tapering upwardly from said antennas and having forward and rear ends closely adjacent said antennas tapering upwardly and outwardly so as to form a smooth continuation of said sides, said fairing thereby creating ground planes with respect to said antennas so that a substantial portion of the radiation pattern emanating from said antennas extends above a generally horizontal plane passing through said antennas perpendicular to a vertical plane through the centerline of the aircraft whereby said aircraft can undergo substantial roll without interrupting the signal pattern to and from said ground control stations.

13. An antenna assembly for an aircraft as described in claim 12 wherein the tapered sides of said fairing are placed so as to define an angle of approximately therebetween.

Drake Aug. 30, 1932 McMillan Nov. 11, 1952 

